Megatherium (Stranger) 12-13-02 17:57 No 389280 |
Super-dry ethanol (Rated as: excellent) |
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This is the Lund and Bjerrum method for preparing super dry EtOH. * Fit a dry 2 litre RB flask with a double surface condenser and a calcium dry tube. * Place 5 g of clean dry Mg turnings and 0.5 of I2 in the flask, followed by 50 - 75 mg of commercial absolute EtOH. * Warm the mixture until the iodine has disappeared. If a lively evolution of hydrogen does not set in, add a further 0.5 g portion of I2. Continue heating until all the Mg is converted into ethanolate * Then add 900 ml of commercial absolute ethanol and reflux the mixture for 30 minutes. * Distill off the EtOH directly into the vessel in which it is to be stored. The purity of the ethanol exceeds 99.5 % provided that adequate precautions are taken to protect the distillate from atmospheric moisture. The super-dry ethanol is very hygroscopic; it may be stored over a Type 4A molecular sieve. |
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